Research on the method of damage theory applied in underground lining structure's durability

Damage or deterioration may occur in underground lining structures under the effects of external loads, groundwater seepage, and corrosive ions. Consequently, the durability and reliability of the structure can be severely affected. This study first analyzed and summarized the current situation of damage theory used in the durability research of concrete structures and underground. Consequently, the concept of a "deterioration degree function, " which can reflect the degree of damage to a structure, was proposed. Subsequently, the Gurson meso-damage model was analyzed for its application in the durability research of underground structures concerning the theory, formulae, and steps. A type of specimen was designed as an example, wherein the track model of steel corrosion expansion as assumed and deduced, and the numerical calculation of the damage stress was calculated to predict the durable life of the structure. The analysis concept developed in this study can be extended and applied to other research fields with similar durability problems.